Much ink has been spilled over the prospect that an SNP wave could devastate Labour in Scotland on May 7, ending that party’s traditional dominance north of the border. By contrast, little attention has been paid to the implications for the Tories – which are dire indeed.

The Conservative Party only has one Scottish Westminster seat – Dumfriesshire, Clydesdale and Tweeddale in the western borders – and current predictions see current MP David Mundell losing to the SNP. If the Conservatives want to retain any connection between their parliamentary party and Scotland, they will need to win somewhere else – and they’ve found a target in the eastern borders constituency of Berwickshire, Roxburgh and Selkirk (BRS).

BRS’s sitting MP is the Liberal Democrat Michael Moore, who was secretary of state for Scotland in the coalition government until being unceremoniously dumped for not being tough enough in the run-up to the 2014 referendum.

This seat is often described as rural, which isn’t quite true. Much of it is farmland or moorland, but most of its people live in small towns or villages, and the great majority of employment is in services. Some residents commute to Edinburgh, and the Waverley line to Tweedbank and Galashiels has been re-opened precisely to help people who work in Edinburgh to live in the Borders, where house prices are much lower. Wages for those who work in the area are low, considerably less than the Scottish average.

The seat’s marginal nature stems in part from the way it has been sliced and diced over the years. Much of it overlaps with the old boundaries of Roxburgh, Selkirk and Peebles, the constituency that Liberal icon David Steel won from a Tory in a 1965 by-election. The rest was largely in the historic Berwick and East Lothian constituency held for Labour by local grandee John Home-Robertson until it was abolished – although most Labour votes were in the mining areas of East Lothian, which are now in a different seat.

In the crosshairs

BRS is firmly in the Tories’ sights for 2015, and they will need it if they want to retain any connection between their parliamentary party and Scotland.

A Conservative MSP, John Lamont, is standing as the Westminster candidate, hoping to displace Moore. But current predictions are that the SNP will narrowly take this seat as well.

This is a remarkable shift given that the Nationalists drew only 9.2% of the votes in 2010, though it was foretold in the independence referendum, when 33.4% of Borders votes went for Yes. That was the second lowest Yes vote of Scotland’s regions; only Orkney was less enthused, But it was a remarkably high figure given the borders’ usual leanings, and it proved that the SNP could win the third of the vote it needs to capture a previously unattainable Westminster seat.

You might not know this if you were on the ground. As it often goes in local campaigns, the parties are busy trying to push their own distinct variations on what’s really happening. Although Lamont’s campaign literature does carry a picture of him with Cameron, it doesn’t mention anywhere that he’s the Conservative candidate. Most of it is devoted to local issues that are under the purview of Holyrood, not Westminster.

Moore’s literature, meanwhile, frantically asks voters to vote Lib Dem to stop the Tories getting a national majority, framing the contest as a straight Lib Dem-Tory faceoff. This is a full-blooded attack on the Tories, with no mention of the SNP at all – even though the latest Aschroft poll of the seat found the Lib Dems running a very close third.

Muddy water

Just to muddy the water, there are other candidates knocking around too. They’re polling very low – but in a seat this tight, every vote counts.

UKIP’s Peter Neilson might well take some crucial votes from the Tories, but there’s no knowing how many. There’s a strong local Green candidate, Pauline Stewart, who was very active in the referendum campaign; she’s done particularly well at school hustings, but many of those who took to her are too young to vote.

Still, the Greens could well take some votes from the SNP and pick up a few tactical Lib Dem voters, and it’s not impossible that Labour could come fifth behind them.

In a recent Scotsman piece, the borders’ resident novelist and right-wing commentator Allan Massie called for a Tory-Lib Dem joint campaign in Scotland to stop the SNP taking rural seats thanks to a split vote. But that’s exactly what might happen in Massie’s own constituency. As things stand, the next Westminster parliament looks set to contain no Tory MPs whatsoever from Scotland – and quite possibly no Lib Dems either.

Overall, the current expectation for BRS is that the SNP will beat the Tories in a tight race – but there are simply too many variables here for that prediction to be confident. So stand by for recounts: this one could be too close to call.